ELECTRON MONOCHROMATOR TIME-OF-FIGHT MASS SPECTROMETER

电子单色仪战斗时间质谱仪

基本信息

批准号：
6524880
负责人：
MAX L DEINZER
金额：
$ 14.02万
依托单位：
OREGON STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-08-01 至 2003-07-31
项目状态：
已结题

项目摘要

The interaction of low-energy electrons with electrophilic molecules in the production of negative ions is an important chemical process. Electron capture negative ion mass spectrometry (ECNI-MS) is a powerful system used for the analysis of very small amounts of such compounds, but in its present forms it can provide only limited information on the processes that produce negative ions. In this application we propose to construct a versatile gas chromatography/electron monochromator-time-of- flight mass spectrometer (GC/EM-TOF-MS). This instrument will be used to elucidate mechanisms of negative ion formation and decomposition via metastable ions. The electron monochromator (EM) to be used generates monoenergetic electron beams with currents of approximately 400 microamps tunable in the range 0- 15eV with maximum energy spreads of O.leV. The electron source when interfaced to the time-of-flight (TOF) analyzer will yield reproducible 3-dimensional spectra whose axes are resonance electron energy mass to charge, and ion signal intensity. The gas chromatographici nlet system, will provide a means to resolve compound mixtures and a stable supply of buffer gas to stabilize resonance electron capture ions. A reflectron in the analyzer will provide the capability to study metastable ions. Experimental resonance electron energies, when correlated with the virtual orbital energies of the molecules calculated by density functional theory methods, will provide information on the orbitals involved during initial ion formation. Electron attachment to several classes of electrophilic compounds including organophosphates, sulfonamides, dinitro [2,2]para- cyclophane, aliphatic ketones, haloethenes, vinyl chloride and chloroacetaldehyde will be investigated. In addition to providing a unique system for studying the mechanistic details of negative ion formation, the sensitivity, specificity, extra dimension of analytical information from resonance electron energies and "fast" GC/MS capability of the proposed GC/EM-TOF MS instrument will make it a valuable new tool for analyzing environmental health-related chemicals, biochemical and biomedical-related compounds that can be derivatized with electrophores. The analysis of proteins, peptides and other biopolymers with electron-capturing posttranslational modifications is another potentially exciting application for the GC/EM-TOF-MS system.

低能电子与亲电分子在负离子产生中的相互作用是重要的化学过程。电子捕获负离子质谱法（ECNI-MS）是一个强大的系统，用于分析非常少量的此类化合物，但在目前的形式中，它只能提供有关产生负离子的过程的有限信息。在此应用中，我们建议构建一种多功能气相色谱/电子单色器时间飞行质谱仪（GC/EM-TOF-MS）。该仪器将用于阐明通过亚稳态离子的负离子形成和分解的机制。用于使用的电子单色器（EM）会产生单晶电子束，其电流在0-15EV范围内可调节的电流约为400微型，并且最大的能量扩散O.Lev。当将电子源连接到飞行时间（TOF）分析仪时，将产生可重复的3维光谱，其轴为谐振电子量和离子信号强度。气相色谱系统将提供一种方法来解决复合混合物和稳定的缓冲气体供应，以稳定共振电子捕获离子。分析仪中的反射量将提供研究可稳离子的能力。实验共振电子能与密度功能理论方法计算的分子的虚拟轨道能相关时，将提供有关初始离子形成过程中涉及的轨道的信息。电子附着在包括有机磷酸盐，磺酰胺，Dinitro [2,2]偏环，脂肪族酮，卤甲烯，氯乙烯，氯化乙烯基和氯乙醛醛的几类的亲电磷酸化合物上的电子附着。 In addition to providing a unique system for studying the mechanistic details of negative ion formation, the sensitivity, specificity, extra dimension of analytical information from resonance electron energies and "fast" GC/MS capability of the proposed GC/EM-TOF MS instrument will make it a valuable new tool for analyzing environmental health-related chemicals, biochemical and biomedical-related compounds that can be derivatized with electrophores. 通过电子捕获后翻译后修饰的蛋白质，肽和其他生物聚合物的分析是GC/EM-TOF-MS系统的另一种令人兴奋的应用。